The board of directors or other officers of the district shall have no power to incur any debt or liability whatever, either by issuing bonds or otherwise, in excess of the express provisions of this article, nor shall they add to the expenditure of any one fiscal year anything over and above the amount provided for in the annual appropriation resolution relating to that year, and any debt or liability incurred in excess of these provisions shall be and remain absolutely void; except that said expenditures may be increased in emergency cases if the same are authorized in writing by a number of district electors equal to one-half the number who voted at the last annual district election.L. 05: p. 264, § 28. R.S. 08: § 3467. L. 15: p. 314, § 1. C.L. § 2006. CSA: C. 90, § 405. CRS 53: § 149-1-29. C.R.S. 1963: § 150-1-29.